Double Fine was founded in July 2000 - on Tim's birthday - to create its first game. That game was released in 2005. Naturally, a project in development for that long is gonna have some production tales worth writing about, which Gamasutra's Game Developer Magazine (discontinued) did when they published a postmortem for Psychonauts, scribed by then Double Fine producer Caroline Esmurdoc, back in August 2005.
I can remember reading it, but apparently a full version has never been thrown online before, or so Gamaustra says in the convenient web version they published yesterday in honor of the game's tenth (!!) anniversary. Check it out!